Wear of ceramic nozzles by dry sand blasting

Monolithic B₄C, Al₂O₃/(W,Ti)C and Al₂O₃/TiC/Mo/Ni ceramic composites, which provided a reasonably wide range of mechanical properties and microstructure, were produced to be used as nozzles materials. The erosion wear of the nozzle caused by abrasive particle impact was compared with dry sand blasting by determining the cumulative mass loss of the nozzles made from these materials. Results showed that the hardness of the nozzle material plays an important role with respect to its erosion wear. On the nozzle entry bore section, the B₄C nozzle appears to be entirely brittle in nature with the evidence of large scale-chipping, and exhibited a brittle fracture induced removal process. While the erosion mechanism of Al₂O₃/TiC/Mo/Ni nozzle appeared to be a preferential removal of the metal binder followed by pluck out of the undermined Al₂O₃ and TiC grains under the same test conditions. On the nozzle center bore zone, the B₄C nozzle fails in a highly brittle manner, and there are lots of obvious micro-cracks and small pits located on this area. While the primary wear mechanisms of Al₂O₃/TiC/Mo/Ni nozzle is plowing and micro-cutting by the abrasive particles. Both types of material removal model seem to be occurred for the Al₂O₃/(W,Ti)C nozzle.